Generally or should i say typically the smaller bucks will start chasing does before they are ready, jumping the gun sort to speak. If a doe is in heat and your area hold a good number of bucks you will typically see more than one buck in the area or giving chase. That is why you sometimes see a smaller buck, then a larger buck further behind a doe, once she is ready that larger buck will run his little foe right out of town. Hang tight if does are coming to your area than bucks will as well, the fact he was feeding shows that his interets are split, a mature buck will not give 2 sh$ts about food come peak rut.